Beefburgers containing horse meat could have been made from “diseased or
injured animals” and be unsafe to eat, environmental health experts say.

The meat posed a health risk because it had not come from identified sources, they warned. “There is no information on how the horse meat came to be in the burgers and so there is no way of telling whether the meat is safe to eat. It could be from diseased or injured animals, for example,” said John Sleith, the head of the Society of Chief Officers of Environmental Health in Scotland.

“If it hasn’t come through the official inspection system, there is no confidence that it is completely harmless.”

The Food Standards Agency has repeatedly said that the meat poses no risk to health. It is considering testing beef products sold in supermarkets for horse and other animals after it was criticised for its “light touch”.

Supermarkets and suppliers in the scandal could face maximum fines of just £5,000 under “toothless” food regulations, experts warned yesterday. David Heath, the food minister, said the Government “clearly wants” prosecutions after Tesco sold beefburgers containing 29 per cent horse.

But lawyers in the UK and Ireland said that criminal action was “highly unlikely”.

Tim Lang, a professor of food policy at City University in London, said: “The regulatory system is toothless.”

An investigation by the Food Safety Authority of Ireland found that four British supermarkets had sold burgers contaminated with horse meat.

Under British law, retailers could face fines of up to £5,000 or prison sentences for breaking European regulations about “misleading presentation of food to consumers”.

A larger fine or term could be imposed at the Crown Court, but lawyers said this would be unlikely if the company could demonstrate that it had shown “due diligence”.

Hilary Ross, an expert in food at London-based lawyers DWF, said: “In my experience it would be highly unlikely that Tesco would be prosecuted for this kind of offence. Retailers don’t set out to give their customers horse meat.”

The law is similar in Ireland, where the two suppliers involved, ABP food group and Liffey Meats, are based. The maximum penalty there is £2,500, with a potential prison term of three months, but no one is thought ever to have been jailed for the offence. ABP insists it has done “nothing wrong” and blames its suppliers on the Continent. Maree Gallagher, an Irish food lawyer, said that prosecution was unlikely and both firms were very reputable, she said.

Tim Smith, Tesco’s group technical director, said: “We will not tolerate any compromise in the quality of the food we sell. The presence of illegal meat in our products is extremely serious. Our customers have the right to expect the highest standards.”